1. Field of the Invention
The present invention relates to an improvement in an intake manifold for an engine, comprising: a plurality of intake distribution pipes arranged in a side-by-side relation to one another along one side wall; an intake inlet pipe provided in one end wall in a direction of arrangement of the intake distribution pipes; a surge chamber provided inside the intake manifold, and providing communication between the intake inlet pipe and the intake distribution pipes; and an intake guide wall provided integrally with the intake manifold, the intake guide wall extending in the direction of arrangement of the intake distribution pipes from an opening end of the intake inlet pipe, which is open to the surge chamber, to an intermediate portion of the surge chamber, and formed to temporarily guide the air, which has been introduced from the intake inlet pipe into the surge chamber, to a middle portion of the surge chamber.
2. Description of the Related Art
Such an intake manifold for an engine has been already known as disclosed, for example, in Japanese Patent Application Laid-open 2002-361745.
This conventional type of intake manifold for an engine includes an intake guide wall which is formed relatively thick to have a higher rigidity so that it is prevented from vibrating even when receiving intake pulsations from the surge chamber. However, for the purpose of reducing the weight of the engine as much as possible, there is a requirement to form the intake guide wall thinner. If the intake guide wall is merely formed thinner, the intake guide wall will then have a reduced rigidity and as a result, it will generate vibration noise.